/*
    This file is part of the iText (R) project.
Copyright (c) 1998-2025 Apryse Group NV
    Authors: Apryse Software.

    This program is offered under a commercial and under the AGPL license.
    For commercial licensing, contact us at https://itextpdf.com/sales.  For AGPL licensing, see below.

    AGPL licensing:
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Affero General Public License for more details.

    You should have received a copy of the GNU Affero General Public License
    along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
using System;
using System.IO;
using iText.Bouncycastleconnector;
using iText.Commons.Bouncycastle;
using iText.Commons.Bouncycastle.Crypto;
using iText.Commons.Bouncycastle.Openssl;

namespace iText.Kernel.Utils {
    public sealed class PemFileHelper {
        private static readonly IBouncyCastleFactory FACTORY = BouncyCastleFactoryCreator.GetFactory();

        private PemFileHelper() {
            // Empty constructor.
        }
        
        public static IPrivateKey ReadPrivateKeyFromPemFile(Stream pemFile, char[] keyPass) {
            return ReadPrivateKey(pemFile, keyPass);
        }
        
        private static IPrivateKey ReadPrivateKey(Stream pemFile, char[] keyPass) {
            using (TextReader file = new StreamReader(pemFile)) {
                IPemReader parser = FACTORY.CreatePEMParser(file, keyPass);
                Object readObject = parser.ReadObject();
                while (!(readObject is IPrivateKey) && readObject != null) {
                    readObject = parser.ReadObject();
                }
                return (IPrivateKey)readObject;
            }
        }
    }
}
